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            <div class="quiz-header">
              <h1>NIO和Reactor模式 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
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      <script>
        const quizData = [
  {
    "question": "与传统的阻塞I/O（Blocking I/O）相比，非阻塞I/O（NIO）最核心的区别是什么？",
    "options": [
      "NIO使用更多的线程来处理连接，因此速度更快。",
      "发起I/O请求后，应用程序会立即返回而不会等待操作完成，从而可以处理其他任务。",
      "NIO只能用于UDP通信，而BIO可以用于TCP。",
      "NIO的数据传输是同步的，而BIO是异步的。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "非阻塞I/O（NIO）的核心在于，当应用程序发起读写请求时，它不会阻塞等待操作完成，而是立即返回控制权。这使得单个线程有机会处理多个I/O请求，从而避免了因等待I/O而造成的资源浪费，极大地提升了系统在高并发场景下的效率。",
    "source": "文档中「什么是NIO（Non-blocking I/O）？」部分",
    "hint": "文档中提到，传统I/O会“阻塞在读取操作上”，而NIO正是为了解决这一问题。"
  },
  {
    "question": "在Netty所使用的Java NIO模型中，`Selector`组件的主要作用是什么？",
    "options": [
      "代表一个网络连接通道，所有I/O操作都通过它进行。",
      "作为数据缓冲区，用于高效地读取和写入字节数据。",
      "作为多路复用器，监听多个`Channel`的I/O事件，并在事件就绪时通知应用程序。",
      "负责创建和管理处理I/O事件的线程池。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`Selector`是Java NIO中的多路复用器，它是实现一个线程管理多个连接的关键。通过将多个`Channel`注册到同一个`Selector`上，线程可以一次性检查所有`Channel`是否有就绪的I/O事件（如可读、可写），从而避免了为每个连接都创建一个线程，也避免了对每个连接进行无效的轮询。",
    "source": "文档中「NIO的核心组件」部分",
    "hint": "这个组件使得用一个线程管理多个连接成为可能，避免了为每个连接都创建一个线程的问题。"
  },
  {
    "question": "根据文档描述，Reactor模式的核心思想是什么？",
    "options": [
      "为每一个客户端连接创建一个独立的线程进行处理。",
      "将I/O事件的接收和事件的具体处理分离开，通过事件分发器分配给不同的处理器。",
      "强制所有I/O操作必须同步执行以保证数据一致性。",
      "将业务逻辑和网络通信代码紧密耦合在一起以提升性能。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "Reactor模式是一种事件驱动的设计模式。它的核心思想是将I/O事件的监听和分发（由Reactor角色负责）与具体的事件处理（由Handler角色负责）解耦。当事件发生时，Reactor负责通知相应的Handler进行处理，从而实现高效的并发事件处理。",
    "source": "文档中「什么是Reactor模式？」部分",
    "hint": "该模式的关键在于“将I/O事件的接收和事件的处理分开”。"
  },
  {
    "question": "在Netty中，`EventLoopGroup`扮演了什么关键角色？",
    "options": [
      "它是一个处理器链，负责按顺序执行数据的编解码和业务逻辑。",
      "管理一组`EventLoop`，其中每个`EventLoop`（通常由一个线程支持）负责处理一个或多个`Channel`的I/O事件。",
      "它是一个服务器启动类，仅用于配置服务器端口和协议。",
      "它是一个用于存储待发送数据的缓冲区队列。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`EventLoopGroup`是Netty中Reactor模式的具体实现。它是一个事件循环组，内部包含一个或多个`EventLoop`。每个`EventLoop`通常由一个独立的线程驱动，负责处理分配给它的所有`Channel`上的I/O事件。这种模型避免了线程间的竞争，并能高效处理大量连接。",
    "source": "文档中「Netty中如何实现NIO和Reactor模式？」部分",
    "hint": "文档提到，这个组件是“管理事件循环的核心组件”，并且“包含多个EventLoop”。"
  },
  {
    "question": "Netty中的`ChannelPipeline`的主要功能是什么？",
    "options": [
      "它是一个独立的线程，用于执行耗时的业务逻辑，防止阻塞I/O线程。",
      "它负责监听服务器端口，并接受新的客户端连接。",
      "它是一个处理器链（`ChannelHandler`的集合），负责按顺序处理流经`Channel`的入站和出站I/O事件。",
      "它负责管理底层NIO的`Selector`，并注册`Channel`。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`ChannelPipeline`提供了一种责任链模式的实现。它包含一系列的`ChannelHandler`，当I/O事件（如数据读取或写入）在一个`Channel`上发生时，该事件会流经`ChannelPipeline`中的各个Handler，每个Handler都可以对事件进行处理、修改或传递，从而实现业务逻辑的解耦和复用。",
    "source": "文档中「Netty中如何实现NIO和Reactor模式？」部分",
    "hint": "这个组件内部包含多个`ChannelHandler`，用于处理数据的解码、业务逻辑、编码等。"
  },
  {
    "question": "为什么说Netty基于NIO和Reactor模式的设计能够实现高并发处理？",
    "options": [
      "因为它为每个连接都创建了一个专用的、轻量级的协程，从而实现了高并发。",
      "因为它通过非阻塞I/O和事件多路复用，使得一个或少数几个线程就能管理成千上万的连接，避免了为每个连接创建线程的巨大开销。",
      "因为它使用了操作系统的阻塞I/O优化，能够更快地从内核复制数据。",
      "因为它强制所有业务逻辑都在一个单线程内同步执行，避免了锁竞争。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "高并发的核心优势来源于对资源的极致利用。传统的“一个连接一个线程”模型在连接数增多时会消耗大量内存和CPU上下文切换开销。Netty通过NIO的非阻塞特性和`Selector`的多路复用能力，可以用极少数的线程（`EventLoop`）来监听和处理海量连接的I/O事件，从而大大降低了资源消耗，提升了系统的并发承载能力。",
    "source": "文档中「Netty的NIO和Reactor模式的优势」部分",
    "hint": "思考一下传统模式下“一个连接一个线程”的瓶颈在哪里，而Netty是如何解决这个瓶颈的。"
  },
  {
    "question": "在提供的`EchoServer`代码示例中，`bossGroup`和`workerGroup`这两个`EventLoopGroup`通常是如何分工的？",
    "options": [
      "`bossGroup`专门负责接收客户端的连接请求，而`workerGroup`则负责处理已建立连接的I/O读写事件和业务逻辑。",
      "`bossGroup`负责处理读事件，`workerGroup`负责处理写事件。",
      "`bossGroup`用于处理TCP连接，`workerGroup`用于处理UDP连接。",
      "两者没有明确分工，Netty会随机将连接分配给其中一个Group处理。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "这是Netty中一种经典的主从Reactor模式实现。`bossGroup`（主Reactor）通常只配置一个线程，它的唯一职责是监听服务器端口并接受新的客户端连接，然后将建立好的连接（SocketChannel）注册到`workerGroup`（从Reactor）中的某个`EventLoop`上。后续该连接上的所有I/O操作都由`workerGroup`中的线程负责，实现了职责分离，提高了处理效率。",
    "source": "文档中「实际应用案例：基于NIO和Reactor模式的Echo服务器」部分",
    "hint": "请仔细观察代码中的注释：`EventLoopGroup bossGroup = new NioEventLoopGroup(1); // 负责接收客户端连接`。"
  }
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                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  